MT-2 (Melanotan II)
MT-2 Regulatory Status
MT-2 holds no marketing authorisation from the MHRA, EMA, FDA or any other regulator. A related melanocortin agonist — afamelanotide — is approved for a specific rare condition, but that is a different molecule and its approval extends to MT-2 in no respect.
Key facts
- MHRA status
- Not authorised
- EMA status
- Not authorised
- FDA status
- Not approved
- Approved relative
- Afamelanotide (Scenesse), different molecule
- Published harms literature
- Yes
- Supply basis here
- Laboratory research only
The position
No regulator has assessed MT-2. There is no marketing authorisation anywhere, no registered clinical trial programme, no label, no contraindications, and no adverse event reporting framework. It is supplied here for laboratory research only.
Three factors that make this the strictest case on the site
First, it is an injectable product rather than a laboratory reagent by usage pattern. Second, a published dermatological harms literature exists. Third, a structurally related compound is an approved medicine, which creates a standing invitation to the wrong inference. No other category here has all three.
Research material referenced
MT-2 10mg — third-party HPLC tested
Why the approved relative raises rather than lowers the risk
Afamelanotide's approval is real, for a serious rare condition, following full assessment. It covers a linear thirteen-residue peptide at 1,646.8 Da. MT-2 is cyclic, seven residues, 1024.2 Da, and unassessed. The numbered naming makes them look like versions of one product, and a database search for the bare name returns the approved one — which is how a plausible-looking verification lands on the wrong molecule.
What is said here and what is not
Reportable: that MT-2 is a cyclic heptapeptide analogue of alpha-MSH at 1024.2 Da, that melanocortin receptors number five with distinct tissue distributions, that MT-2 is described as non-selective across them, and that a published safety literature exists including case reports of atypical melanocytic naevi. Not said, in any form: anything about tanning, pigmentation, appearance or any effect in any person.
The enforcement context
The MHRA opened investigations into UK retailers making therapeutic or cosmetic claims about unregulated products in April 2026. For an unlicensed injectable with published case reports and an approved lookalike, the margin for imprecise language is effectively zero — which is why this category carries no framing beyond the chemistry, the pharmacology and the literature.
Extended research context
The MT-2 (Melanotan II) deep dive
Deep dive: the identifier collision that points the wrong way
This site has now found several plausible-looking identifiers that resolve to the wrong molecule. A PubChem record for tirzepatide cited as retatrutide. Thymosin beta-4's CAS quoted as TB-500's. An unrelated organic acid returned for KPV. This one is the most consequential of the set, and the reason is direction. Searching PubChem for melanotan returns CID 16197727 - afamelanotide, at 1,646.8 Da for C78H111N21O19. That is Melanotan I, a linear thirteen-residue peptide, and it is an APPROVED MEDICINE, marketed as Scenesse for erythropoietic protoporphyria. Melanotan II is CID 92432: cyclic, seven residues, 1024.2 Da, 622 Da lighter, and assessed by no regulator anywhere. So the wrong record does not merely mislead about mass. It resolves from an unlicensed compound toward a licensed one, and the sequential naming - I and II - makes them look like versions of a single product rather than the structurally distinct compounds they are. Anyone verifying a certificate by searching the bare name lands on an approved drug's record and may never notice which compound it names.
Deep dive: four stability features in seven residues
PubChem's IUPAC name for CID 92432 is unusually complete and reads as a full specification: N-acetyl-L-norleucyl-L-alpha-aspartyl-L-histidyl-D-phenylalanyl-L-arginyl-L-tryptophyl-L-lysinamide, cyclic (2-7)-peptide. Unpack it and there are four independent protease-resistance features in a molecule of seven residues. A lactam bridge joins the aspartate side chain at position 2 to the lysine side chain at position 7, closing the ring - which both locks conformation for receptor engagement and eliminates the free termini exopeptidases require. Position 4 is D-phenylalanine, the mirror image of the natural form, and proteases are stereospecific enough that they largely cannot process it. The N-terminus is acetylated and the C-terminus amidated, capping both ends. And position 1 is norleucine, which is not among the twenty proteinogenic amino acids at all - so even setting aside the cyclisation and the D residue, this peptide could never have been a gene product. It is a fully synthetic construction rather than a modified natural sequence, and it is among the most chemically robust compounds in this catalogue as a direct result.
Deep dive: why the safety literature is included rather than omitted
There is a published dermatological literature here, and the editorial choice was to state it. Reid and colleagues documented atypical melanocytic naevi following melanotan injection in the Irish Medical Journal in 2013. Eijmael and colleagues published a risk review in the Nederlands Tijdschrift voor Geneeskunde in 2022 - a national medical journal considering the topic worth addressing directly. Case reports have a real limitation: they establish an observation without a denominator, so they cannot establish causation or incidence, which is the same constraint that applies to pharmacovigilance disproportionality signals. But that limitation cuts both ways. A case report is not proof of harm and it is not dismissible either. What makes the absence of better data significant here is that no regulator has assessed this compound - so there is no label, no contraindications, no adverse event reporting requirement and no monitoring framework. The information that would normally exist for an injectable product simply does not, and what is available instead is what individual clinicians chose to publish after seeing something. Presenting the compound without that context would give an incomplete picture of what is actually known.
Research applications
- ▸Melanocortin receptor pharmacology and selectivity research
- ▸Cyclic peptide and lactam bridge design studies
- ▸D-amino acid substitution and protease resistance research
- ▸Structure-activity work on constrained peptide analogues
- ▸Comparative work on alpha-MSH derivatives
- ▸Analytical method development for cyclic peptides
Handling checklist
- ✓Verify against CID 92432, 1024.2 Da, C50H69N15O9, CAS 121062-08-6
- ✓Never verify by searching 'melanotan' alone - that returns afamelanotide at 1,646.8 Da
- ✓Require stereochemistry on the certificate - D-Phe4 is not detectable by mass
- ✓Protect from light; tryptophan at position 6 is photochemically reactive
- ✓Store lyophilised, cold, dry and dark
- ✓Expect no disulfide or oxidation satellites - no cysteine, no methionine
- ✓Quantification at 280 nm is available thanks to the tryptophan
Common research-handling mistakes
Learnt from thousands of researcher orders across our UK labs.
✗ Searching PubChem for 'melanotan' to verify identity
Fix: That returns CID 16197727, afamelanotide, at 1,646.8 Da - an approved medicine and a different molecule. Use CID 92432 or search Melanotan II with the numeral.
✗ Treating Melanotan I and II as versions of one compound
Fix: They differ by 622 Da, by six residues, and by whether the peptide is cyclic or linear. Only Melanotan I has been assessed by regulators.
✗ Reading afamelanotide's approval as covering MT-2
Fix: Different molecule, different structure, different evidence, different assessment. Nothing transfers.
✗ Accepting a sequence written without stereochemistry
Fix: L- and D-phenylalanine have identical mass. A peptide with the L form at position 4 is a different compound that mass spectrometry cannot distinguish.
✗ Assuming a non-selective agonist affects only its intended receptor
Fix: Five melanocortin receptors share binding surfaces across different tissues. Engagement elsewhere is the same pharmacology in another place, not a side reaction.
Continue researching
Peer-reviewed guides, comparators and matched reference materials.
Related questions researchers ask
- Why does searching for melanotan return an approved medicine?
- What is the difference between Melanotan I and Melanotan II?
- How do four separate modifications make one small peptide protease-resistant?
- What are the five melanocortin receptors and where are they?
- How do MT-2 and KPV relate through their shared parent hormone?
- What does the published dermatology literature actually report?
Frequently asked questions
- Is MT-2 legal in the UK?
- It is supplied as a material for laboratory research. It is not a licensed medicine and cannot be prescribed or dispensed.
- Isn't there an approved version?
- Afamelanotide is approved for erythropoietic protoporphyria, but it is a different molecule — linear, 13 residues, 622 Da heavier. Its approval does not extend to MT-2.
- Why does this category carry no product framing?
- It is an unlicensed injectable with a published harms literature and an approved compound easily confused with it. The articles cover chemistry, pharmacology and the literature only.
Primary sources & clinical trials
Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.
- RefMHRA — Medicines and Healthcare products Regulatory Agencygov.uk
- PubMedReid C et al. — Ir Med J 2013 (PMID 23914578)pubmed.ncbi.nlm.nih.gov
- PubMedEijmael MJPM et al. — Ned Tijdschr Geneeskd 2022 (PMID 35736369)pubmed.ncbi.nlm.nih.gov
- EMAEuropean Medicines Agencyema.europa.eu
- PubMedKim ES et al., Afamelanotide: a review in erythropoietic protoporphyria — Am J Clin Dermatol 2016 (PMID 26979527)pubmed.ncbi.nlm.nih.gov
- PubMedWensink D et al., Afamelanotide for prevention of phototoxicity in EPP — Expert Rev Clin Pharmacol 2021 (PMID 33507118)pubmed.ncbi.nlm.nih.gov
- PubChemPubChem · Melanotan II (CID 92432)pubchem.ncbi.nlm.nih.gov
- PubChemPubChem · Afamelanotide (CID 16197727)pubchem.ncbi.nlm.nih.gov
- GuidelineGoogle — Creating helpful, reliable, people-first contentdevelopers.google.com
Written and reviewed by
Jack Muncaster · Founder, UK Peptides
Jack founded UK Peptides in Manchester after repeatedly receiving research compounds with missing or recycled paperwork. He is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate.
More MT-2 (Melanotan II) articles
- A 1995 Paper, and a Structure That Checks Out ExactlyHruby's Ac-Nle4-cyclo[Asp5, D-Phe7, Lys10] framework is MT-2's architecture described under alpha-MSH numbering. Every element agrees.
- Alpha-MSH Engages Four of Five, Not All of ThemMC2R recognises ACTH peptides essentially alone. The other four recognise alpha-MSH — a distinction usually flattened into 'the melanocortin receptors'.
- A Third Approved Melanocortin MedicineBremelanotide is a melanocortin receptor agonist that received regulatory approval in 2019 — another compound from the same hormone family as MT-2.
- The Pharmacology Works. This Compound Was Not Developed.Afamelanotide, setmelanotide and bremelanotide all hold approvals. MT-2 holds none — and the difference is development history, not chemistry.
- The Receptor That Decides Which Pigment Is MadeMC1R does not control how much pigment is produced so much as which kind. Variants in it underlie red hair, and the receptor has consequences beyond colour.
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